A fluoroscopic apparatus will be described as an example of X-ray diagnostic apparatus. The following construction is conventionally known for generating a roadmap image in this type of fluoroscopic apparatus.
As X rays are emitted from an X-ray tube to a patient, a flat panel X-ray detector outputs X-ray detection signals. Based on the X-ray detection signals, a data processor acquires X-ray images corresponding to transmitted X-ray images of the patient. The X-ray images acquired are stored in an X-ray image memory, and the X-ray images and operating menus and so on required for X-ray radiography can be displayed on a display monitor.
The data processor has a first subtraction image acquiring unit, a second subtraction image acquiring unit and a superimposition image acquiring unit. The first subtraction image acquiring unit acquires a first subtraction image as a contrast imaging subtraction image selectively showing a blood vessel filled with a contrast medium. The first subtraction image is obtained, based on the X-ray detection signals outputted from the flat panel X-ray detector in response to the X-ray emission from the X-ray tube, from an image subtraction process carried out on a radiographic image of the patient before a contrast medium injection as a mask image and a radiographic image of the patient after the contrast medium injection as a live image.
The second subtraction image acquiring unit acquires a second subtraction image without background parts (e.g. the skull) as a non-contrast imaging X-ray fluoroscopic image. The second subtraction image is obtained, based on the X-ray detection signals outputted from the flat panel X-ray detector in response to the X-ray emission from the X-ray tube, from an image subtraction process carried out on a fluoroscopic image having undergone a real-time smoothing process as a mask image and a fluoroscopic image without the real-time smoothing process as a live image.
The superimposition image acquiring unit acquires a superimposition X-ray image by superimposing, through an image addition process, the contrast imaging subtraction image acquired by the first subtraction image acquiring unit and selectively showing the blood vessel, and the non-contrast imaging X-ray fluoroscopic image acquired by the second subtraction image acquiring unit and not showing background parts (e.g. the skull).
The data processor has an image negative/positive reversing unit for carrying out, as necessary, a negative/positive reversal of the contrast imaging subtraction image acquired by the first subtraction image acquiring unit and selectively showing the blood vessel.
The above construction allows X-ray fluoroscopy with a blood vessel roadmap excluding the skull, which would obstruct confirmation of the blood vessel, to be carried out easily in real time (see Patent Document 1, for example).
[Patent Document 1]
Unexamined Patent Publication No. 2006-34355